By Darren Hefty: I know we have shown this on Ag PhD over the winter, but I wanted to talk one more time about Corn Rootworms and potential resistance before you plant your corn this spring. There were several fi elds of corn with a rootworm trait that went down in Eastern South Dakota and Western Minnesota last year. To avoid falling into the same trap on your farm, here is what you need to do.

1. Switch to SmartStax. The biggest benefi t of SmartStax traited corn is that you get both the Herculex trait from Dow/Mycogen AND the YieldGard trait from Monsanto. By having multiple modes of action, corn rootworms and other pests have a much smaller chance of becoming resistant to your Bt’s. The other big advantage for you with SmartStax is the reduction in refuge requirements to 5%.

2. Use Insecticide. Even where we are planting SmartStax on our farm, and especially where we’re planting VT3, we’ll continue to use some insecticide at planting time…either 1/3 or 1/2 the normal rate of Force or Aztec. Keep in mind that with corn rootworm traits, the insects must take a bite of the corn plant’s roots to be controlled. With insecticides, corn rootworms and many secondary pests can be eliminated before they chew off those roots. Liquid products like Capture LFR work pretty well, but if you have dry boxes Force and Aztec are still the best. If you just got or are planning to get a new planter, we strongly recommend equipping it with insecticide capabilities, either using a liquid system for products like Capture LFR or Regent OR getting regular dry boxes or a Smart Box system to apply dry insecticides. Talk to us about the programs that will help you getone of those systems for free or at a reduced cost.

3. Control Volunteer Corn. This sounds a little out of place, but controlling the volunteer corn in your soybean fi elds can help you reduce your chance of seeing corn rootworms becoming resistant to the Bt traits. Volunteer corn may still have some amount of the corn rootworm trait in it, but often times that trait will not be as strong as it needs to be. Allowing rootworms to feed on any volunteer corn gives them the host crop they need to make it through their life cycle and reproduce. Plus, if the trait has been weakened, rootworms can potentially build resistance by consuming sub-lethal doses of the Bt. Rootworms are in the larvae stage in late May through late June or early July. By controlling volunteer corn with your FIRST PASS in Roundup Ready soybeans, you take away that host crop for rootworms, and you’ll help break the resistance cycle.

You may or may not have corn rootworms resistant to Bt’s on your farm right now. After seeing some of the corn in the same section where Brian lives go down this year, we can tell you fi rst hand that you want to do everything you can so that problem doesn’t happen to you. Take steps this year to reduce your chances for rootworm issues and potential resistance.